1)
Why did Haman add that only he was invited?
1.
Malbim: He told how he reached the highest level. It is proper to call all Sarei ha'Melech to the queen's Mishteh. We never hear of a Mishteh for one or two people - "va'Ya'as ha'Melech Mishteh Gadol l'Chol Sarav va'Avadav" (2:18). I am so great in the queen's eyes that I am equated to all Sarei ha'Melech!
2)
Why did he add that he was invited also tomorrow?
1.
Malbim: She needs to request something from the king, and she fears lest he refuse, and called also me, that I will request for her to fulfill her request. This shows that I am greater than the queen, and she needs me!
